JP2008108902A - Surface-mounted type electrolytic capacitor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a configuration providing a sufficient soldering strength, when soldering and mounting a surface-mounted type electrolytic capacitor on a circuit board surface. <P>SOLUTION: Tip parts 13a and 14a of a positive electrode terminal 13 and a negative electrode terminal 14, constituting a resin case 12 of a surface-mounted type electrolytic capacitor, protrude from the resin case 12. The tip parts 13a and 14a are bent toward the upper part in a figure, substantially vertical to the bottom surface of the resin case 12, so that exposed faces of the tip parts 13a and 14a are formed on the side surface of the surface-mounted type electrolytic capacitor. Notches 11a are formed at parts of a jacket case 11 that abut against the tip parts 13a and 14a. When mounting by soldering on a circuit board surface is carried out, since a solder flows around to the vertical exposed surfaces of the tip parts 13a and 14a and a fillet is formed to the circuit board surface, rigid soldering and fixing can be implemented. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a surface mount electrolytic capacitor suitable for a decoupling circuit of a power supply line, and more particularly to a terminal structure thereof.

  In a CPU (central processing unit) of a computer, it is necessary to use a decoupling element mainly composed of a capacitor in order to prevent generation of noise superimposed on the power supply line. The problem of noise generated in the power supply line is becoming more important as the CPU clock is improved, and decoupling in the use of the power supply line in personal computers, servers, digital home appliances, communication equipment, etc., whose speed and frequency are increasing The need for devices is increasing.

  The decoupling element is also called a transmission line type element or a transmission line type noise filter. As a decoupling element, it has a capacity of several hundred μF, ESR (equivalent series resistance) in a frequency band of 100 MHz is 5 mΩ or less, and ESL (equivalent series inductance) is about 1 pH, and has both a capacitor and a filter function. Surface mount electrolytic capacitors have been developed and put into practical use. A surface mount type electrolytic capacitor is generally formed by laminating a plurality of layers of electrolytic capacitor elements. Each electrolytic capacitor element has a dielectric film formed on an anode made of a foil-like or plate-like valve metal. Further, a cathode portion made of a solid electrolyte and a conductive substance is formed. The anode portions of the upper and lower adjacent electrolytic capacitor elements are connected to each other via a conductive paste, and the cathode portions are similarly connected to each other via a conductive paste. The anode part and the cathode part at the lowermost end are connected to the anode terminal and the cathode terminal through conductive paste, respectively.

  As a conventional example of such a surface mount electrolytic capacitor, there is an example described in Patent Document 1. A conventional example will be described with reference to FIG. 5A is an exploded view of the surface mount electrolytic capacitor described in Patent Document 1, FIG. 5B is an external perspective view, and FIG. 5C is a bottom view thereof. In FIG. 5, a resin case 52 is formed by molding a plurality of electrode terminals made of a metal plate with resin, and two anode terminals 53 and cathode terminals 54 made of metal are molded integrally with the resin. And a box-like shape without a lid portion, which is composed of a bottom surface and four side surfaces made of resin alone. Further, tip portions 53 a and 54 a are respectively formed on part of the anode terminal 53 and the cathode terminal 54. A single-layer or multi-layer electrolytic capacitor element (not shown) is housed and fixed in the resin case 52, and an outer case 51 is placed and bonded and fixed from above in the figure to constitute a surface-mount type electrolytic capacitor. In the resin case 52, an anode and a cathode of an electrolytic capacitor element (not shown) are connected and fixed to the anode terminal 53 and the cathode terminal 54, respectively.

  In the conventional surface mount type electrolytic capacitor, since the electrode terminal which is a soldering region exists only on the bottom surface, there is a problem that the soldering fixing strength is small. In general, when soldering electronic components to the circuit board surface, the soldered area of the electronic component is wetted by the solder and connected and fixed, and there is an area where the solder surface is exposed, called a fillet, around the soldered area. Need to be formed. However, in an electronic component in which the electrode terminals for soldering are provided only on the bottom surface of the element, the soldering area is only the surface facing the circuit board surface, and no fillet is formed around it. There was a case that could not get.

  In the case of the surface mount type electrolytic capacitor described in Patent Document 1, a fillet is formed by providing a tapered tip portion on a part of a metal anode terminal and a cathode terminal, and a relatively large soldering strength is provided at the time of mounting. It is configured to be obtained. An enlarged view of the vicinity of the tip is shown in FIG. FIG. 6A is a perspective view of the vicinity of the tip, and FIG. 6B is a cross-sectional view of the main part when soldering is actually performed on the circuit board surface. In FIG. 6, the front end portion 64 is formed in a direction perpendicular to the resin case side surface 62 and protrudes in a direction parallel to the circuit board 65. Here, since the vicinity of the end portion of the front end portion 64 is formed in a taper shape, the thickness gradually decreases as it approaches the front end. Therefore, the vicinity of the end portion of the front end portion 64 warps 67 against the circuit board surface. have. When soldering is performed, solder flows into the warped region and a solder fillet 66 is formed with respect to the circuit board 65. Therefore, the circuit board 65 and the tip portions 64 of the anode terminal and the cathode terminal are relatively strong. It is possible to fix it by soldering.

JP 2006-128247 A

  Since the tapered region provided at the tip of the electrode terminal of the surface mount electrolytic capacitor in Patent Document 1 is limited to an amount smaller than the thickness of the anode terminal and the cathode terminal, The fillet that is actually formed is fairly small. Therefore, when the surface mount electrolytic capacitor is miniaturized, the fillet formed is also small, resulting in a problem that the soldering strength is lowered. In addition, if it is necessary to inspect the electrical characteristics after soldering and mounting the surface mount type electrolytic capacitor to the circuit board surface, the tips of the anode and cathode terminals are small, so the inspection is performed. It cannot be used as a contact point. Therefore, for the inspection, it is necessary to provide an inspection contact on the circuit board in advance, which may be a restriction on the design of the circuit board.

  Accordingly, an object of the present invention is to obtain a sufficient soldering strength for mounting even when the surface mount type electrolytic capacitor is miniaturized, and even on the circuit board even after the solder mounting on the circuit board surface. It is an object of the present invention to provide a structure of a surface mount type electrolytic capacitor that enables measurement of electrical characteristics without providing the above element.

  In order to solve the above-mentioned problems, in the present invention, a resin case having a bottom surface and a side surface, in which an anode terminal and a cathode terminal made of a metal plate are molded with a resin, and the resin case is covered from above and bonded and fixed. In the surface mount type electrolytic capacitor having an outer case, the tip portion of both the anode terminal and the cathode terminal constituting the resin case of the surface mount type electrolytic capacitor protrudes from the resin case. Is bent in a direction substantially perpendicular to the bottom surface of the resin case, and the tip portion forms an exposed surface on the side surface of the surface mount electrolytic capacitor. When this surface mount type electrolytic capacitor is soldered and mounted on the circuit board surface, the solder wraps around the vertical exposed surface of the tip of this electrode terminal, and a sufficiently large fillet is formed between the surface and the circuit board surface. Due to the formation, it is possible to implement a strong soldering fixation.

  Further, it is preferable that the exterior case of the surface mount electrolytic capacitor is configured so that a notch is provided in a region where the exposed surface exists so that the exposed surface is not hidden by the exterior case. Since the shape and size of the exposed surface are arbitrary, the notch provided in a part of the side surface of the outer case may be provided so as to leave the upper end portion in the height direction of the side surface portion of the outer case. The entire region in the height direction including the upper end portion may be removed. Moreover, a notch may be provided only in two surfaces among the side parts of an exterior case, and may be provided in all four surfaces. Further, the outer case may be configured such that the exposed surface is positioned outside the outer case without providing a notch.

  That is, the present invention is a plate-like electrolytic capacitor element having an anode portion at the end and a cathode portion at the center, or an electrolytic capacitor element laminate formed by laminating the capacitor elements, and is flat with each other. And an anode terminal connected to the anode part, a cathode terminal connected to the cathode part, and a gap between the anode terminal and the cathode terminal on the plane that is not occupied by the mold. In addition, both the terminals are fixed, and a resin case having a bottom surface part where the lower surfaces of both terminals are exposed, and a side wall that is substantially perpendicular to the bottom surface part, an upper part of the resin case, and the In the surface mount type electrolytic capacitor, comprising a box-shaped outer case covering a part of the side wall, the anode terminal and the cathode terminal arranged on the bottom surface of the resin case An end portion protrudes from an edge portion of the bottom surface portion, and the tip end portion forms a side surface portion extending upward in a direction substantially perpendicular to the bottom surface portion, and the side surface portion is A surface-mount type electrolytic capacitor characterized in that it is exposed at a part of a side surface of an outer case.

  Further, according to the present invention, a cutout portion is provided in a part of a side surface of the outer case, and the side surface portion in a substantially vertical direction of the anode terminal and the cathode terminal is formed on the side surface of the outer case. It is a surface mount type electrolytic capacitor characterized by being inserted into a notch.

  According to the present invention, the tip portion of the anode terminal and the cathode terminal protrudes from the side surface of the surface mount type electrolytic capacitor and extends upward in a substantially vertical direction to form the side surface portion. In this case, a sufficiently large solder fillet can be formed at this location, and therefore, firm soldering and fixing can be performed on the circuit board surface. In this case, when a cutout corresponding to the terminal portion is provided on the side surface of the outer case, there is an advantage that the outer dimension of the outer case is not increased by providing the side surface portion. Furthermore, even after the surface mount type electrolytic capacitor is soldered and mounted on the circuit board surface, by using the formed side surface as a contact for measurement, a special measurement contact can be provided on the circuit board. It is possible to measure the electrical characteristics of the surface mount type electrolytic capacitor without mounting it again from the circuit board surface after mounting.

  A surface mount electrolytic capacitor according to an embodiment of the present invention will be described with reference to FIGS.

  FIG. 1 shows a surface mount type electrolytic capacitor according to a first embodiment of the present invention. 1A is an exploded view showing the resin case and the exterior case separately, FIG. 1B is an external perspective view, and FIG. 1C is a bottom view. In FIG. 1, a resin case 12 has a box shape without a lid, as in the conventional example described in Patent Document 1, and includes two anode terminals 13 and a cathode terminal 14 made of a metal plate. Is formed of a resin and is integrally formed with a bottom surface and four side surfaces made of only resin. A single-layer or multilayer electrolytic capacitor element (not shown) is housed and fixed in the resin case 12, and the anode and cathode of the electrolytic capacitor element are connected to the anode terminal 13 and the cathode terminal 14 in the resin case 12, respectively. It is fixed. An outer case 11 is placed on the resin case 12 from the upper side of the figure and bonded and fixed to form a surface mount type electrolytic capacitor.

  Further, tip portions 13 a and 14 a are respectively formed on part of the anode terminal 13 and the cathode terminal 14. The tip portions 13a and 14a are obtained by extending the anode terminal 13 and the cathode terminal 14 to the outside of the resin case 12, and the tip portion protruding from the bottom of the resin case 12 is directed upward in the drawing along the outer surface thereof. By being bent substantially vertically, a solderable metal surface reaching the middle height is formed on the side surface of the resin case 12. Further, the outer case 11 is formed with notches 11a for the portions that abut the tip portions 13a and 14a, so that the tip portions 13a and 14a are not covered by the outer case 11 after assembly. .

  FIG. 2 shows a surface mount type electrolytic capacitor according to a second embodiment of the present invention. 2A is an exploded view showing the resin case and the exterior case separately, FIG. 2B is an external perspective view thereof, and FIG. 2C is a bottom view thereof. The configurations of the resin case 22 and the outer case 21 are the same as those of the first embodiment, and the tip portions 23a and 24a of the anode terminal 23 and the cathode terminal 24 are arranged on the upper side of the figure along the side surface of the resin case 22. Although it is the same in that it is bent substantially perpendicularly, the height of the tip portions 23a, 24a is higher than the side surface of the resin case 22, and is substantially the same as the upper surface of the outer case 21 during assembly. Further, the notches 21 a provided on the side surfaces of the outer case 21 are also enlarged in accordance with the heights of the front end portions 23 a and 24 a and reach the upper surface of the outer case 21. Such a configuration is particularly effective in forming a fillet in a low profile surface mount electrolytic capacitor.

  Further, FIG. 3 shows a surface mount electrolytic capacitor according to a third embodiment of the present invention. 3A is an exploded view showing the resin case and the exterior case separately, FIG. 3B is an external perspective view, and FIG. 3C is a bottom view. The configurations of the resin case 32 and the outer case 31 are the same as those of the first embodiment, and the tip portions 33a and 34a of the anode terminal 33 and the cathode terminal 34 are directed upward along the side surface of the resin case 32. It is the same in that it can be bent almost vertically. However, unlike the case of the first embodiment, the tip 33a extending from the anode terminal 33 is also different from the other side surface on the narrower side surface of the resin case 32 located in the left-right direction in the figure. Similarly, a metal surface capable of being soldered is formed on the side surface of the resin case 32. In addition, a cutout 31a is formed in the outer case 31 at the portion in contact with the distal end portion 33a in the same manner as the others so that the outer case 31 does not cover the distal end portion 33a during assembly. In such a configuration, the tip end portion of the electrode terminal provided on the side surface of the resin case increases, so that the fixing force in soldering can be further improved.

  Finally, FIG. 4 shows a surface mount type electrolytic capacitor according to a fourth embodiment of the present invention. 4A is an exploded view showing the resin case and the exterior case separately, FIG. 4B is an external perspective view, and FIG. 4C is a bottom view. The configuration of the resin case 42 and the outer case 41 is the same as that of the first embodiment, and the tip portions 43a and 44a of the anode terminal 43 and the cathode terminal 44 are arranged along the side surface of the resin case 42 in the upper part of the figure. The front end portions 43a and 44a are bent so as not to contact the side surface of the resin case 42, leaving a gap corresponding to the thickness of the side surface of the exterior case 41. The resin case 42 is covered with an outer case 41 from the upper side of the drawing and fixed by bonding to form a surface mount type electrolytic capacitor. However, since the outer case 41 is not provided with a notch, 43a, 44a is not the resin case 42 but forms a solderable metal surface on the side surface of the outer case 41. In this configuration, the area occupied by the surface mount electrolytic capacitor is slightly larger than that of the other embodiments of the same performance. In such a configuration, since it is not necessary to provide a cutout in the outer case, the manufacturing process of the outer case can be simplified.

  With the configuration of each of the embodiments described above, when the surface mount type electrolytic capacitor according to the present invention is soldered and fixed to the circuit board surface, a fillet is formed around the electrode terminals to be soldered. It is explained that the soldering is realized. At the same time, the electrode terminal can be used as a contact when measuring the electrical characteristics of the surface mount electrolytic capacitor. The above description does not limit the invention described in the scope of claims or reduce the scope of the claims. Moreover, each part structure of this invention is not restricted to the said embodiment, A various deformation | transformation is possible within the technical scope as described in a claim.

The figure which shows the surface mount type electrolytic capacitor in the 1st Embodiment of this invention. 1A is an exploded view, FIG. 1B is an external perspective view, and FIG. 1C is a bottom view. The figure which shows the surface mount-type electrolytic capacitor in the 2nd Embodiment of this invention. 2A is an exploded view, FIG. 2B is an external perspective view, and FIG. 2C is a bottom view. The figure which shows the surface mount-type electrolytic capacitor in the 3rd Embodiment of this invention. 3A is an exploded view, FIG. 3B is an external perspective view, and FIG. 3C is a bottom view. The figure which shows the surface mount-type electrolytic capacitor in the 4th Embodiment of this invention. 4A is an exploded view, FIG. 4B is an external perspective view, and FIG. 4C is a bottom view. The figure which shows the conventional surface mount-type electrolytic capacitor. 5A is an exploded view, FIG. 5B is an external perspective view, and FIG. 5C is a bottom view. The enlarged view of the vicinity of the front-end | tip part of an anode terminal or a cathode terminal in the conventional surface mount-type electrolytic capacitor of FIG. FIG. 6A is a perspective view, and FIG. 6B is a cross-sectional view of the main part when soldering is actually performed on the circuit board surface.

Explanation of symbols

11, 21, 31, 41, 51 Exterior case 11a, 21a, 31a Notch 12, 22, 32, 42, 52 Resin case 13, 23, 33, 43, 53 Anode terminal 13a, 23a, 33a, 43a, 53a Tip Portions 14, 24, 34, 44, 54 Cathode terminals 14a, 24a, 34a, 44a, 54a Tip portion 62 Resin case side surface 64 Tip portion 65 Circuit board 66 Solder fillet 67 Warpage

Claims (2)

A plate-shaped electrolytic capacitor element having an anode part at the end and a cathode part at the center, or an electrolytic capacitor element laminate formed by laminating the capacitor elements;
An anode terminal that is flat with respect to each other and arranged on the same plane and connected to the anode part, a cathode terminal connected to the cathode part,
On the plane, the gap between the terminals of the anode terminal and the cathode terminal is molded and the both terminals are fixed, and a bottom surface portion is formed by exposing a lower surface of the both terminals. A resin case having side walls that are substantially perpendicular to the surface;
In the surface mount type electrolytic capacitor, characterized by comprising a box-shaped outer case covering the upper part of the resin case and a part of the side wall,
The anode terminal and the tip of the cathode terminal arranged on the bottom surface of the resin case protrude from the edge of the bottom surface, and the tip is upward in a direction substantially perpendicular to the bottom surface. A surface-mounting type electrolytic capacitor, characterized in that an extended side surface portion is formed and the side surface portion is exposed at a part of the side surface of the exterior case. A cutout portion is provided in a part of the side surface of the exterior case, and the side surface portion of the anode terminal and the cathode terminal in a substantially vertical direction is fitted into the cutout portion on the side surface of the exterior case. The surface mount type electrolytic capacitor according to claim 1, wherein

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